We always drive in power mode, randomly I will notice that the car would switch to EV mode even when cruising at fairly high speed 40 mph+. As long as I go easy on the gas pedal it will stay in the EV mode and maintain the speed. But it doesn't always do this on it's own, what's the control logic to get it to the EV mode to maintain speed when cruising?
You must differentiate between "Modes" and the state of the system. Modes select special settings: EV tries to maintain pure electric drive at low speeds with little pedal pressure. "Power" and "Eco" mode mainly adjust the way the pedal responds to inputs: Power a little more, Eco a little less (while it also changes the way AC works). Although you can set modes, there are certain driving states that allow the system to switch the ICE off and run electrically altough you did not select EV Mode. The system will do so automatically but will not switch to this mode. How to work the car to switch off ICE? Best way is the HSI (Hybrid System Indicator). Keep pedal pressure low and HSI in the left broad range (not the charge range) and the ICE will soon switch off (if engine and outside temperature permit).
I understand the different switchable driving modes. "certain driving states that allow the system to switch the ICE off and run electrically although you did not select EV Mode." What I am wondering about is the "certain driving states", because even if I left off the gas once I reached my desire speed and lightly feather the gas it will not go into this mode, but sometimes it just jumps to this mode right away. Could be on the same road between 2 red lights, it will behave differently. I am curious of the parameters that the computer decides to do that.
My experience is, that the difference comes mainly from outside temperature, engine temperature and weather influence (headwind, wet road conditions). So often you can not really put the car to coast in electric mode because of unfavorable conditions...
That's what drives me crazy and want to find out the parameters to get it to go into EV cruise, I was on the same flat road, same temperature, same day, same time and everything...
search for the warming up stages thread. It pretty well answers this to the extent we have figured it out. Of course, being in EV is often the wrong choice for max fuel economy, ours being gas cars and all. Good luck.
First thing to realize is that EV operation is almost always less efficient than gasoline. You have to burn gas to run the Motor Generators to power the inverter to charge the battery where it is converted to a chemical charge; then reconvert the chemical charge back to DC electricity and convert the DC back to AC to run the Motor Generators. This almost always wastes more energy than running on gasoline. However, if I slow gently from a sustained 55 (for 30 miles, say, so the car is warm) down to 30 without coming to a stop, I can use EV for almost a mile as I regened power slowing from 55 to 30. Very small throttle openings are the gas engine's least efficient mode, so sometimes all that work to run in EV mode is less wasteful. I never plan to use EV, but it happens when the computers feel it is the least wasteful way to travel.
So basically meaning the Prius was design to take the driver out of the equation..... I drive the Prius according to certain Prius logic, heavy throttle on take off to get up to speed quickly and let off and keep off the pwr zone. Cruise whenever possible, and lightly tap the brake pedal to charge the battery at a higher rate. Watch traffic ahead and cruise etc etc etc, so I pretty much can average 50+mpg easily with the Prius. That's why I was interested to find out how the cruise/EV mode is activated because IMHO that's the most efficient way to drive the Prius. I am not worried about the battery not being the most efficient way to produce energy because I get plenty of charge using braking and slowing down to charge the battery up. My wife in the other hand don't follow any rules, she drives it like a sports car and only gets about 35 mpg...
You make good points! I try to use CC as much as possible? Ever watch how quick that computer adjusts. It amazes me. I think the engineers reall have the CC logic biased quite well.
